Showing papers presented at "European Conference on Power Electronics and Applications in 1995"

A symmetrical 3 phase - 2 switch PFC-power supply for variable output voltage

Abstract: Power Factor Corrected rectifiers are a new tendency in development of power supplies. In the last few years, a lot of RD activities have led to a new category of products for one phase applications. In this comtribuction, a new simplified topology is proposed for three-phase applications, using only two active switches, and able to generate symmetrical currents in the line. Power circuits are presented. Complete simulator results with closed loop operation are given, results of an experimental verification.

Using multimedia in variable speed drive teaching

Abstract: Abstract The paper provides ideas and practical experiences using multimedia at the electrical engineering department in the field of electrical machines and variable speed drives. Using multimedia develpments, it is possible to confront students in a more attractive and efficient way with Electrical Machines and Drives. The paper approaches the term multimedia from different points of view The definition of a multimedia computer is explained and different authoring systems are presented. A practical example, visualisation of phenomena and construction of a squirrel cage induction machine, is looked at in a closer way. The conclusion is that the undergraduates gel more interested and even recommend additional multimedia applications in other topics of electrical engineering education.

A CAD laboratory in electromagnetics for undergraduates

Abstract: The CAD laboratory gives the students an idea when to use the different approaches to deal with magnetic circuits. They start with a simplified analytical model and are then confronted with the finite element method, even in three dimensions. Calculations and measurements are compared and discussed.

Influence of switching frequency and squirrel cage design on audible noise and losses in variable speed induction motor drives with transistor and IGBT inverters

Abstract: A large number of experiments are performed to analyse the influence of the inverter type and the switching frequency on the audible noise, losses and overall efficiency in induction motor drives. Temperature measurements both in stator and rotor give an indication of the required derating, if any. Results for a standard design motor, consecutively supplied by a transistor based inverter and IGBT inverter are compared with the behaviour when the machine is directly connected to the mains. To analyse the influence of the rotor design, a special rotor with no current redistribution is constructed and mountedin a rewound stator. Higher switching frequencies have a large influence on audible noiseand temperature, but the overall efficiency remains nearly constant. However the distribution of losses is influenced.